Underreamer.



A. G. HEGGEM.

UNDERRBAMEB.

APPLICATION FILED JUNE 29, 1908.

Patented June 29, 1909.

allow UNITED STATES PATENT OFFICE.

ALFRED G. HEGGEM, OF GORAOPOLIS, PENNSYLVANIA, ASSIGNOR TO OIL WELL SUPPLY COMPANY, OF PITTSBURG, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

UNDERRE AMER.

Specification of Letters Patent.

Patented June 29, 1909.

Application filed June 29, 1908. Serial No. 440,938.

To all whom it may concern:

Be it known that I, ALFRED G. HEGGEM, a citizen of the United States, residing at Coraopolis, in the county of Allegheny and State of Pennsylvania, have invented certain new and useful Improvements in Underreamers; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention relates to the construction of that class of devices known as underreamers, em(ployed for enlar ing the bore of Artesian an like drilled wells where casing is used, and the tool has to be introduced and withdrawn through the casing. In this class of devices the reaming bits must be colla sible on the bit stock in order that the too may be passed through the casing, and it is desirable that the length of the bit-stock and bits be limited, and that the resilient element which maintains the bits in their normal position shall have suflicient initial tension to maintain the bits firmly in said position and yet its ultimate tension when the bits are' drawn down or collapsed shall not be excessive. To accomplish these objects I combine in an underreamer, a bit-stock having an axial bore and lateral abutments, bits slidingly connected .With the bit-stock, and a tension spring ad'ustably anchored at one end to the bit stoc and having its other end connected with the bits, and such a construction embodies the main feature of my invention.

A second feature of my invention embraces the combination in an underreamer, of a bit-stock having an axial bore, lateral abutments and a distance-block, bits slidingly connected with the bit-stock, a bitsupport, a tension spring anchored at one end to the bit-stock and having its other end connected with the bits, and a compression spring interposed between the bits and supported by the distance-block of the stock.

A third feature-of my invention embraces the combination in an underreamer, of a bitstock having lateral abutments, bits slidingly connected with the bit-stock, a bit-support, a bit-support clamp, and a tension spring anchored at one end to the bit-stock and at the other end to the bit-support clamp.

There are other, minor, features of invention, embracing particular combinations and features of elemental construction, all as will hereinafter more fully appear.

In the drawings chosen for the purpose of illustrating my invention, the scope whereof is pointed out in the claims, Figure 1 is a longitudinal central section of the bit-stock and one bit of an underreamer embodying my invention, the other bit being in elevation.

Fig. 2 a view in elevation of the lower end of the bit-stock and bit. Fig. 3 is a view in elevation similar to Fig. 2 but at right angles thereto. Fig. 4 is a transverse section on the line 4-4, Fig. 1. Fig. 5 is an enlar ed detail view of the bit-support clamp an spring plug the latter being in section.

Like symbols refer to like parts wherever they occur.

I will now roceed to describe my nvention more ful y so that others skilled in the art to which it appertains may apply the same. 0

In the drawings, 1 indicates the bit-stock having at opposite oints in its perlphery the bit-recesses 2, 2, or the reception of the tangs of the reamer bits, the top walls of sa1d recesses 2, 2, being fiat as at 2 to constltute solid abutments for the flat upper ends of the bit-tangs. the bit recesses 2, 2 are channeled as at 2', 2 to form ways for the reception of lateral ribs on the tangs of the reamer-bits and sald w ays narrow slightly from below upward to ermit of sufficient lateral play of the bits tor the expanding and collapslng ofsaid blts, as will hereinafter appear. The blt-stock 1 has also on its lower end upwardly and inwardly inclined abutments 2, 2 and 1nter mediate thereof a distance-block 3 against the lateral walls of which the inner faces of the reamer-bits abut when they are in their normal or operative position.

The bit-stock 1 is formed wlth an axial bore 4 which extends from its upper end, where it is provided with an annular shoulder 4, down to the distance-block 3, where it terminates, forming at a point between the bits and on the upper surface of said (llStBJfCG block 3 a spring chamber 3 for the reception and retention of a compression sprlng of which the distance-block forms the support. The walls of the spring chamber 3 are slotted as at 3 for the passage and vertical play therein of a bit-su port.

5, 5 indicate tiie reamer-bits which are slidingly connected with the bit-stock 1 by The lateral inner or side Walls of means of laterally projecting ribs 5 on the bit tangs 5 a which enter the ways or channels 2 2 in the side walls of the bit-recesses 2, 2. The upper ends of the tangs 5 of the bits 5 are flat to seat solidly on the abutments 2 and farther down, the bits 5, 5 are provided with upwardly and inwardly inclined shoulders, as at 5, 5 to engage similarly inclined abutments 2, 2 on .the lower end of the bitstock 1.

The interior faces of the bits are cut back or recessed as at 5 to accommodate the intermediate distance-block 3 when the bits are drawn down and collapsed, and the tangs of the bits are slotted as at 5 to receive the bit support by which said bits are loosely supported or sus ended so as to be bodily movable on said )it support.

6 indicates a bit support preferably in the form of a thin bar or key adapted to pass through and move Vertically in the slot 3 in the walls of the spring chamber 3, and to enter the slots 5 in the tangs of the bits.

7 indicates a compression spring located between the bits within the spring chamber 3 and intermediate of the bit-support 6 which it carries and the distance-block 3 on which it rests.

8 indicates a tension spring located in the bore 4 of the bit-stock to which it is anchored at its u per end, and above the bit-support 6 to whic it is connected at its lower end.

The (preferred means of anchoring the upper on of the tension s ring 8 to the stock, consists of an annular p ug 9 threaded on its outer surface or otherwise constructed to engage the upper end of said tension spring 8, and interiorlyas in case of a nut, to receive the threaded end of a screw, or threaded bolt 10 which bolt passes through a central opening 1n a disk 11, supported in the bore 4 of the stock by resting on the annular shoulder 4 means Will also serve to adjust the initial tension' of spring 8. The preferred means for connecting the tension spring 8 to the bit-support 6 is of similar character, that is to say, to the extent of including an annular plug 9 threaded on its exterior and interior, and a threaded bolt or screw 10 but said threaded bolt 10 terminates in an eye forming an eyebolt or stirrup 1.0 the lower bar of which is adapted to enter a recess or seat 6 on the under side of the bitsupport 6, and the under side of annular plug 9 is cupped out as at 9 so that it can be screwed down .over the shoulder of the stirrup 10 to clamp the bit-support 6 Within the bore of the bit-stock and hold it securely in the stirrup and against endw'ise movement or displacement.

In assembling the several parts which go to make up the underreamer, the compression spring 7, when used, is first introduced through bore 4 into spring chamber 3 so as to rest on top of distance-block 3, next the plugs 9, 9 with their adjunctsincluding the stirrup 10 and disk 11are secured to the tension spring 8, care being had not to screw the plug9 home on stirrup 1 0 which would prevent the subsequent introduction of bit-support 6, and the spring and its ad-v juncts are then introduced 1nto axial bore 4 of the bit-stock 1. Next the tangs 5 of bits 5 are introduced into bit-recesses 2, 2 of the bit stock with the lateral ribs 5 of tan s 5 in' the ways or channels 2 2 in the si e walls of bit recesses, thus forming a sliding dovetailed connection between the bit-stock and bits. The bits are then pressed up until they are solidly seated on the abutments 2 and 2 of the stock after which the compression spring7 is compressed until the bit-support 6 can be passed through the slots 5 of the bit-tangs and the slot 3 in the walls of the spring chamber 3*, after which the bit-support 6 is introduced and secured by rotating tension spring 8 to force the cupped plug 9 down over stirrup 10 and cause it to clamp and hold the bit-support 6.

When, in employing the underreamer constructed as herein set forth, it is desired to introduce the same into and through the easing, the bits 5 are drawn down until the recesses 5 are opposite thedistance-block 3 after which they are forced inward to the position indicated by the dotted lines in Fig. 1 of the drawings, or collapsed. This puts compression spring 7 under compression and, tension spring 8 under tension, and in this condition the tool is introduced into the easing. The walls of the casing retain the bits in the collapsed, or dotted line, position until the bits emerge from the lower end of the casing, whereupon upon the release of the bits the reaction of the springs force the bits into/ their normal or operative relation to the bitstock, as shown in the full lines of the draw- In withdrawing the underreamer from the well, the outer faces of thebit tangs engage the lower end of the casing which retains the bits until such time as the continued upward movement of the stock has brought the distance-block 3 o posite the recesses 5 on the inner faces of t tle bitswhich is permitted by the compression of spring 7 and extension of spring 8whereupon the bits 5, 5 collapse, or again assume the position shown in dotted lines in Fig. 1 of the drawing, which permitsthe tool to pass into and through the casing.

It will be noted that as the tension spring will be a close coiled spring and the com ression spring an cpen coiled spring, t ese springs supplement each other in their action on the bits and insure stability and effectiveness, and it will also be noted that if desired the compression spring may be omittedand an operative combmation will still exist, and that, by reason of the tension spring being initially a close coil, the bit-stock and bits may be of the minimum effective length, and yet the length of the sprin will admit of a hi h initial tension, which Wi lhold the bits firm y on the abutments of the stock, Without making the ultimate tension of the spring, when the bits are collapsed, too great for practical use.

Having thus described my invention, What I claim and desire to secure by Letters Patent is:

1. In an underreamer, the combination of a bit-stock having an axial bore, lateral abutments, and a distance-block, bits slidingly connected with the bit-stock, a tension spring anchored to the bit-stock at one end, and connected with the bits at the other end, and a compression s ring intermediate of the bits and supporte' on the distanceblock for supplementing the tension sprin and holding the bits normally expanded an in contact With the lateral abutments of the bit-stock.

2. In an underreamer, thecombination of a bit-stock having an axial-bore and lateral abutments, bits slidingly connected with the bit-stock, a bitsupport, a bit-support clamp, and a tension spring anchored at one end to the bit-stock and havingits' other end connected with the bit-support clamp.

3. In an underreamer, the combination of a bit-stock having an axial bore, lateral abutments, and a distance-block, bits slidingly connected With the bit-stock, a bitsupport, a tension sprin anchored at one end to the bit-stock an having its other end connected with the bit-sup 0117, and a compression spring beneath the it su port and supported by the distance-bloch for supplementing the tension spring and holding the bits in normal engagement With the lateral abutments of the bit-stock.

4. In an underreamer, the combination of a bit-stock, bits slidingly connected with the bit-stock, a tension spring connected at one end with the bits, and an externally threaded plug nut and threaded bolt for anchoring the other end 01' the tension spring on the bitstock.

5. In an underreamer, the combination of a bit-stock, bits slidingly connected with the bit stock, a bit support, a tension spring SiLOCK which prevents the displacement of the bit-support.

7. In an underreamer, the combination of a bit-stock having an axial bore and a bitsupport slot intersecting said bore, bits slidingly connected with the bit-stock, and movable on the bit support a bit-support which passes through the bit-support slot of the bit stock, a spring for holding the bits normally expanded and means for clamping one end of the said spring to said bitsupport.

In testimony whereof I afiix my signature, in presence of two subscribing Witnesses.

ALFRED G. HEGGEM.

l/Vitnesses:

EMMA H. GOODWIN, W. WV. ANDERSON. 

